This invention is related in general to the field of telecommunications. More particularly, the invention is related to a method for signalling connection control part message loop prevention.
The network evolution as a result of the recent telecommunications bill has resulted in the need for global title databases that require complex and precise inter-network coordination to ensure proper delivery of Signalling System No. 7 (SS7) Signalling Connection Control Part (SCCP) messages. This newly added requirement and complexity has increased the burden on network administrators and administration systems. Any inaccuracies occurring during the provisioning process of the global title databases by the network administrators and administration systems can result in SCCP message looping. SCCP message looping occurs as a message is routed repeatedly through a number of network elements in the telecommunications network, without ever reaching its final destination.
The recently approved version of ANSI SS7-SCCP-1996 standards provide procedures for the prevention of SCCP message looping. These procedures, however, require network services that are sending SCCP messages utilize the extended unitdata (XUDT) and extended unitdata service (XUDTS) defined messages. The XUDT and XUDTS messages have an SCCP hop counter parameter that is used to count the number of times a message has been processed by a network element, so that the message can be terminated if it has traversed a predetermined number of network elements.
Currently, XUDT and XUDTS messages are not supported in the telecommunications network. It is very costly for network providers to modify existing services from the UDT and UDTS message formats which are currently in use to the generation of XUDT and XUDTS message formats. The modification would require changes to every service switching point (SSP), signal transfer point (STP), and service control point (SCP) in the service provider""s network.
Accordingly, a need has arisen for a solution to message looping without costly modifications to every service switching point, signal transfer point, and service control point in the telecommunications network.
In one aspect of the invention, a method for preventing message looping in a telecommunications network includes the steps of receiving a UDT/S query message, determining a next destination for processing the query message and a route for delivering the query message to the next destination. A determination is then made as to whether the route to the next destination is XUDT/S capable. The UDT/S query message is converted to an XUDT/S format by changing the message type encoding and by inserting a hop counter therein if the route is XUDT/S capable. The query message is then delivered to the next destination via the route. The hop counter in the query message is then decremented at the next destination in response to receiving a message of the XUDT/S format. A message loop error is recognized and processed when the hop counter reaches a predetermined value.
In another aspect of the invention, a method for preventing message looping in a telecommunications network includes the steps of receiving a query message, and determining a next destination for processing the query message and a route for delivering the query message to the next destination. Next, a determination is made as to whether the route to the next destination is XUDT/S capable, and whether the query message is an XUDT/S message. The query message is converted to an XUDT/S message by changing the message type encoding and by inserting a hop counter therein if the route is XUDT/S capable and the query message is not an XUDT/S message. The query message is converted to a UDT/S message by changing the encoding to a UDT/S message and removing the hop counter therein if the route is not XUDT/S capable and the query message is an XUDT/S message. At the next destination, the hop counter is decremented in the XUDT/S query message. The query message is discarded if the hop counter reached a predetermined value.